{
  "abstract": "We study the doubly heavy open-flavor tetraquarks $T_{bc}^{(0)}$ ($J^{P}=0^{+}$) and $T_{bc}^{(1)}$ ($J^{P}=1^{+}$) in the dynamical diquark model, treating them as heavy antidiquark--light diquark systems interacting through the lattice-QCD $Σ_g^+(1S)$ Born--Oppenheimer potential. Solving the radial Schrödinger equation gives $M(T_{bc}^{(0)})=7.143$--$7.158$ GeV and $M(T_{bc}^{(1)})=7.217$--$7.222$ GeV, with hyperfine splittings $Δ_{HF}\\simeq59$--$79$ MeV. The splitting is driven mainly by the mass difference between symmetric and antisymmetric heavy-antidiquark configurations, while the chromomagnetic contribution satisfies $\\partialΔ_{HF}/\\partialκ_{\\bar b\\bar c}=2$, as required by heavy-antidiquark spin algebra. The mean separation, $\\langle r\\rangle\\simeq0.45$--$0.46$ fm, and inverse radius, $\\langle1/r\\rangle^{-1}\\simeq0.33$--$0.34$ fm, show weak parameter dependence and support a compact diquark--antidiquark picture. The scalar mass lies essentially at the $B\\bar D$ threshold, allowing either a weakly decaying bound state or a narrow near-threshold structure. The axial-vector state lies $23$--$28$ MeV above $B^{*}\\bar D$ and about $70$ MeV below $B\\bar D^{*}$, making it a natural $S$-wave resonance candidate with a line shape sensitive to the nearby $B^{*}\\bar D$ threshold. Parametric uncertainties are dominated by the light-diquark mass and largely cancel in mass differences. We also complete the $Σ_g^+(1S)$ multiplet: its four isovector members follow from the isoscalar states by a rigid shift $2κ_{ud}\\approx206$ MeV and lie above all $B^{(*)}\\bar D^{(*)}$ thresholds. Finally, the neglected $\\bar{\\mathbf6}\\otimes\\mathbf6$ configuration is estimated to lie $0.1$--$0.3$ GeV higher and to affect the spectrum only at second order.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2605.05150",
  "author_total": 1,
  "authors": [
    {
      "name": "Halil Mutuk"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/3d4371e710sh7.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2605.05150",
  "fulltext_url": null,
  "id": "3d4371e710sh7",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2605.05150",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "hep-ex"
    ],
    [
      "arxiv",
      "hep-lat"
    ],
    [
      "arxiv",
      "hep-ph"
    ],
    [
      "arxiv",
      "nucl-th"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2605.05150",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-04",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/3d4371e710sh7.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:27:01Z",
      "native_id": "2605.05150",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2605.05150"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-ex",
      "subfield": "high-energy"
    },
    {
      "field": "physics",
      "origin": "arxiv:nucl-th",
      "subfield": "nuclear"
    }
  ],
  "title": "The $T_{bc}$ tetraquarks near the $B\\bar{D}$ threshold",
  "title_text": "The T_bc tetraquarks near the BD̅ threshold",
  "type": "preprint",
  "updated_at": "2026-10-30T12:27:01Z",
  "url": "https://research.draconitic.com/paper/3d4371e710sh7",
  "venue": "arXiv",
  "versions": []
}